Travel speed control method, apparatus, computing device, and storage medium

ABSTRACT

This application relates to a travel speed control method, an apparatus, a computing device, and a storage medium. The method includes: determining a sampling interval matching a current traveling speed; selecting, starting from a current location, sampling points on an expected traveling route according to the sampling interval; determining a target curvature according to curvatures of the expected traveling route at the respective sampling points; determining, according to the target curvature, a speed limit of traveling on the expected traveling route; and controlling a traveling speed according to the speed limit.

RELATED APPLICATION

This application claims priority to PCT Application No.PCT/CN2018/101038, filed on Aug. 17, 2018, which in turn claims priorityto Chinese Patent Application No. 201710725387.0, entitled “TRAVEL SPEEDCONTROL METHOD, APPARATUS, COMPUTING DEVICE, AND STORAGE MEDIUM” filedwith the Chinese Patent Office on Aug. 22, 2017. The two applicationsare incorporated by reference in their entirety.

FIELD OF THE TECHNOLOGY

This application relates to the field of driving control technologies,and in particular, to a travel speed control method, an apparatus, acomputing device, and a storage medium.

BACKGROUND OF THE DISCLOSURE

With rapid development of science and technologies, technologies aboutdriving control are increasingly advanced, and automated driving isdrawing more attention. To ensure safety of driving, during automateddriving, a speed limit of a road is determined for speed planning,thereby ensuring safe driving.

When calculating a driving speed, a corner route is often segmentedfirst, and a speed limit value of each segment is calculated in advanceand recorded on a map. When a vehicle is traveling through the corner,speed limits recorded on the map in a segmented manner are queried.Often, an abrupt acceleration or deceleration is likely to occur at aboundary between two segments with different speed limits, resulting ina sudden speed changes. For example, if a speed limit of a road segmentis 100 km/s, and a next road segment is relatively curved and has aspeed limit of 60 km/s, a sudden speed change may occur at theconnecting point of the two road segments.

SUMMARY

One aspect of the present disclosure provides a method for controllingtravel speed. The method includes: determining a sampling intervalmatching a current traveling speed; selecting, starting from a currentlocation, sampling points on an expected traveling route according tothe sampling interval; determining a target curvature according tocurvatures of the expected traveling route at the respective samplingpoints; determining, according to the target curvature, a speed limit oftraveling on the expected traveling route; and controlling a travelingspeed according to the speed limit.

Another aspect of the present disclosure provides a travel speed controlapparatus. The apparatus includes a sampling interval determiningmodule, configured to determine a sampling interval matching a currenttraveling speed; a sampling point selection module, configured toselect, starting from a current location, sampling points on an expectedtraveling route according to the sampling interval; a target curvaturedetermining module, configured to determine a target curvature accordingto curvatures of the expected traveling route at the respective samplingpoints; a speed limit determining module, configured to determine,according to the target curvature, a speed limit of traveling on theexpected traveling route; and a travel speed control module, configuredto control a traveling speed according to the speed limit.

Another aspect of the present disclosure provides a vehicle with atravel speed control apparatus. The travel speed control apparatusincludes a sampling interval determining module, configured to determinea sampling interval matching a current traveling speed of the vehicle; asampling point selection module, configured to select, starting from acurrent location, sampling points on an expected traveling routeaccording to the sampling interval; a target curvature determiningmodule, configured to determine a target curvature according tocurvatures of the expected traveling route at the respective samplingpoints; a speed limit determining module, configured to determine,according to the target curvature, a speed limit of traveling on theexpected traveling route for the vehicle; and a travel speed controlmodule, configured to control a traveling speed of the vehicle accordingto the speed limit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic diagram of a system architecture involved in someembodiments of this application.

FIG. 1B is a schematic diagram of a system architecture involved in someother embodiments of this application.

FIG. 1C is a schematic flowchart of a travel speed control method In oneembodiment of this application.

FIG. 2 is a schematic flowchart of a sampling point curvaturedetermining step In one embodiment of this application.

FIG. 3 is a schematic diagram of curvature calculation In one embodimentof this application.

FIG. 4 is a schematic flowchart of a target curvature obtaining step Inone embodiment of this application.

FIG. 5 is a schematic flowchart of a historical reference curvatureobtaining step In one embodiment of this application.

FIG. 6 is a schematic flowchart of a target curvature generating step Inone embodiment of this application.

FIG. 7 is a schematic flowchart of a travel speed control method inanother embodiment of this application.

FIG. 8 is a block diagram of a travel speed control apparatus In oneembodiment of this application.

FIG. 9 is a block diagram of a travel speed control apparatus in anotherembodiment of this application.

FIG. 10 is a schematic diagram of an inner structure of a computingdevice In one embodiment of this application.

DESCRIPTION OF EMBODIMENTS

To make the objectives, technical solutions, and advantages of thisapplication clearer and more comprehensible, the following furtherdescribes this application in detail with reference to the accompanyingdrawings and embodiments. It should be understood that the specificembodiments described herein are merely used to explain this applicationbut are not intended to limit this application.

This application provides a travel speed control method, applicable to asystem architecture shown in FIG. 1A and FIG. 1B. As shown in FIG. 1Aand FIG. 1B, the system architecture includes: a vehicle 101 and acomputing device 102. The computing device 102 may be a computerterminal or a server. In some embodiments, the computing device 102 is aterminal, and the computing device 102 may be located in the vehicle101. The computing device 102 may be integrated in the vehicle 101, andfor example, may be an operating system of the vehicle 101 or a deviceindependent of the vehicle 101. As shown in FIG. 1A, when the computingdevice 102 is a server, the vehicle 101 may be connected to thecomputing device 102 through a network 103, as shown in FIG. 1B. In someembodiments, when the vehicle 101 is in an automated driving mode, thecomputing device 102 may determine a sampling interval matching acurrent traveling speed; select, starting from a current location,sampling points on an expected traveling route according to the samplinginterval; determine a target curvature according to curvatures of theexpected traveling route at the respective sampling points; determine,according to the target curvature, a speed limit of traveling on theexpected traveling route; and control a traveling speed of the vehicle101 according to the speed limit, thereby ensuring safe driving of thevehicle 101.

FIG. 1C is a schematic flowchart of a travel speed control method In oneembodiment of this application. In this embodiment, applying the travelspeed control method to a computing device is mainly used as an examplefor description. The computing device may be a terminal or a server.Referring to FIG. 1C, the method specifically includes the followingsteps.

S102: Determine a sampling interval matching a current traveling speed.

The sampling interval matching the current traveling speed indicatesthat the current traveling speed affects a size of the samplinginterval.

In one embodiment, the sampling interval is positively correlated to thecurrent traveling speed. Specifically, if the current traveling speed ishigher, the sampling interval is larger; and if the current travelingspeed is lower, the sampling interval is smaller.

In one embodiment, step S102 includes: obtaining a current travelingspeed and a preset time length; and determining a sampling intervalaccording to a product of the current traveling speed and the presettime length.

Specifically, In one embodiment, the computing device may directly usethe product of the current traveling speed and the preset time length asthe sampling interval. In another embodiment, the determining a samplinginterval according to a product of the current traveling speed and thepreset time length includes: determining the product of the currenttraveling speed and the preset time length; obtaining a preset samplinginterval; and obtaining a minimum value of the product of the currenttraveling speed and the preset time length and the preset samplinginterval as the sampling interval.

In one embodiment, the computing device may obtain the sampling intervalaccording to the following formula:d=MIN(d ₀ ,V*t ₀),where d is the sampling interval, d₀ is the preset sampling interval, Vis the current traveling speed, and t₀ is the preset time length. In oneembodiment, d₀ may be 10 m, and t₀ may be 0.5 s.

For example, if the current traveling speed V is 15 m/s, d₀ is 10 m, andt₀ is 0.5 s, V*t₀=7.5 m, and then, d=MIN(d₀, V*t₀)=MIN(10, 7.5)=7.5 m.

In another embodiment, step S102 includes: determining a presettraveling speed range within which the current traveling speed falls,and searching for, according to a correspondence between the presettraveling speed range and a sampling interval, the sampling intervalcorresponding to the preset traveling speed range within which thecurrent traveling speed falls.

Specifically, the correspondence between the traveling speed range andthe sampling interval is preset in the computing device. The computingdevice may determine the traveling speed range within which the currenttraveling speed falls, and searching for the sampling intervalcorresponding to the determined traveling speed range according to thecorrespondence, that is, determining the sampling interval matching thecurrent traveling speed.

For example, if the traveling speed falls within a range of 20 to 25m/s, a corresponding sampling interval is 10 m, if the traveling speedfalls within a range of 26 to 30 m/s, a corresponding sampling intervalis 15 m, and if a traveling speed falls within a range of 31 to 35 m/s,a corresponding sampling interval is 30 m. If the current travelingspeed is 28 m/s, a range within which the current traveling speed fallsis 31 to 35 m/s, and further, a matched sampling interval is 30 m.

S104: Select, starting from a current location, sampling points on anexpected traveling route according to the sampling interval.

The expected traveling route is a route that is predicted to be traveledon. The expected traveling route may be a route formed by a road aheadof a vehicle in a current traveling direction.

Specifically, the computing device may select, starting from a currentlocation, sampling points on an expected traveling route according tothe sampling interval. For example, a preset quantity may be 5.

The computing device may alternatively determine a quantity of samplesmatching the current traveling speed and select, starting from a currentlocation and based on the determined quantity of samples, samplingpoints on an expected traveling route according to the samplinginterval. In one embodiment, the quantity of samples is positivelycorrelated to the current traveling speed.

S106: Determine a target curvature according to curvatures of theexpected traveling route at the respective sampling points.

A curvature of the expected traveling route at a sampling pointrepresents a value of a degree by which the expected traveling routedeviates from a tangent of the sampling point, that is, a value of abending degree of the expected traveling route at the sampling point. Alarger curvature indicates a larger degree by which the expectedtraveling route deviates from the tangent of the sampling point, thatis, a larger bending degree of the expected traveling route at thepoint. The target curvature is a curvature finally used to determine aspeed limit (that is, a maximum speed) of traveling on the expectedtraveling route.

Specifically, the computing device may select a maximum curvature fromcurvatures at the respective sampling points, and determine the targetcurvature according to the selected maximum curvature. In oneembodiment, the computing device may directly select the maximumcurvature as the target curvature. In another embodiment, the computingdevice may alternatively obtain an average value of the selected maximumcurvature and curvatures at the auxiliary points, and determine thetarget curvature according to the average value of the curvatures.

S108: Determine, according to the target curvature, a speed limit oftraveling on the expected traveling route.

The speed limit of traveling on expected traveling route is a maximumspeed of traveling on the expected traveling route.

In one embodiment, step S108 includes: obtaining a preset lateral forcecoefficient; obtaining an absolute value of the target curvature; anddividing a product of the lateral force coefficient and the accelerationof gravity by the absolute value of the target curvature and thenextracting a square root to obtain the speed limit of traveling on theexpected traveling route.

A lateral force coefficient is a used to measure a degree of stabilityof a traveling object when the traveling object travels on a travelingroute.

Specifically, the computing device may obtain a speed limit of travelingon the expected traveling route according to the following formula:Vmax=sqrt(u*g/fabs(k _(A))), where

Vmax is a speed limit of traveling on the expected traveling route; u isa lateral force coefficient; g is the acceleration of gravity; k_(A) isa target curvature; sqrt(u*g/fabs(k_(A))) represents performingcalculation to extract a square root from u*g/fabs(k_(A)); fabs(k_(A))represents obtaining an absolute value of k_(A). In one embodiment, thelateral force coefficient u may be 0.2.

S110: Control a traveling speed according to the speed limit.

Specifically, the computing device may perform speed planning accordingto the speed limit, and determine a speed of traveling on the expectedtraveling route.

In the foregoing travel speed control method, the sampling intervalmatches the current traveling speed, and sampling points are selected onthe expected traveling route according to the sampling interval, so thatthe sampling point are more likely to reflect requirements of travelspeed control at the current traveling speed. Determining the targetcurvature according to the curvatures at the selected sampling point canbetter reflect a bending status of the expected traveling route, so thata corner can be found in advance, and further, a speed limit isdetermined according to a curvature of the corner, thereby accuratelycontrolling a traveling speed and reducing sudden speed changes.

As shown in FIG. 2, In one embodiment, before step S106, the methodfurther includes a sampling point curvature determining step,specifically including the following steps:

S202: For each sampling point, consecutively select, starting from thesampling point, two first auxiliary points on the expected travelingroute by using a preset reference length that is less than the samplinginterval as an interval.

The preset reference length is less than the sampling interval. It maybe understood that because two first auxiliary points are consecutivelyselected starting from the sampling point by using the preset referencelength on the expected traveling route, and an arc length between thesampling point and the first auxiliary point, and an arc length betweentwo first auxiliary points are both preset reference lengths.

In one embodiment, the preset reference length may be a vehicle axlelength. The vehicle axle length is a distance from a center of a frontaxle of a vehicle to a center of a rear axle of the vehicle.

S204: Determine a curvature at the sampling point according to an angleformed by connection lines between the sampling point and the respectivefirst auxiliary points and a straight-line distance between the twofirst auxiliary points.

An angle may be formed by connection lines between the sampling pointand the respective corresponding first auxiliary points. Thestraight-line distance between the two first auxiliary points is alength of a line segment between the two first auxiliary points.

In one embodiment, the computing device may determine curvatures atrespective sampling points according to the following method:K _(s)=2*sin(θ/2)/L, whereK_(s) is a curvature at a sampling point, and θ is an angle formed byconnection lines between the sampling point and respective correspondingfirst auxiliary points; and L is a straight-line distance between twofirst auxiliary points.

It may understand that when the preset reference length is a vehicleaxle length, because the vehicle axle length is relatively short, an arclength between two first auxiliary points is approximately equal to astraight-line distance between two first auxiliary points, the vehicleaxle length may be directly substituted as L into the formula above forcalculation.

FIG. 3 is a schematic diagram of curvature calculation In oneembodiment. As shown in FIG. 3, P1, P2, P3, and P4 are sampling points,and a point A and a point B are first auxiliary points corresponding toP1 on an expected traveling route w. The preset reference length betweenthe first auxiliary point and the sampling point P1 is less than thesampling interval between the two sampling points, and θ is an angleformed by connection lines between the sampling point P1 and thecorresponding first auxiliary points, namely, the point A and the pointB.

In the foregoing embodiment, for each sampling point, two firstauxiliary points on the expected traveling route are consecutivelyselected, starting from the sampling point, by using a preset referencelength that is less than the sampling interval as an interval. Acurvature at the sampling point is determined according to an angleformed by connection lines between the sampling point and the respectivefirst auxiliary points and a straight-line distance between the twofirst auxiliary points. During curvature calculation, by making twofirst auxiliary points, a relatively complex calculus curvaturecalculation method is converted into direct calculation between an angleand a distance, which simplifies processing steps and improvesefficiency of obtaining curvatures at sampling points, thereby improvingefficiency of driving speed control.

As shown in FIG. 4, In one embodiment, step S106 (the target curvatureobtaining step for short) specifically includes the following steps.

S402: Determine a target sampling point having a maximum curvature inthe respective sampling points.

The target sampling point is a sampling point having a maximum curvaturein the respective sampling points.

Specifically, the computing device may determine curvatures atrespective sampling points, and selects a sampling point having amaximum curvature from the respective sampling points as the targetsampling point.

S404: Select second auxiliary points respectively in front of and behindthe target sampling point on the expected traveling route according to apreset interval shorter than the sampling interval.

The preset interval is less than the sampling interval. It may beunderstood that an arc length between the second auxiliary point infront of the target sampling point and the target sampling point and anarc length between the second auxiliary point behind the target samplingpoint and the target sampling point are both equal to the presetinterval. The second auxiliary point in front of the target samplingpoint is a point selected, starting from the target sampling point, onthe expected traveling route according to the preset interval in adirection opposite to a traveling direction. The second auxiliary pointbehind the target sampling point is a point selected, starting from thetarget sampling point, on the expected traveling route according to thepreset interval in the traveling direction.

In one embodiment, at least one second auxiliary point in front of orbehind the target sampling point is selected. A same quantity of secondauxiliary points may be selected in front of or behind the targetsampling point. It may be understood that when a plurality of secondauxiliary points is selected in front of or behind the target samplingpoint, an arc length between every two adjacent second auxiliary pointsis equal to the preset interval.

S406: Obtain the target curvature according to a curvature at the targetsampling point and curvatures at the second auxiliary points.

In another embodiment, the computing device may alternatively obtain anaverage value of a curvature at the target sampling point and curvaturesat the second auxiliary points, and determine the target curvatureaccording to the obtain average value of the curvatures.

Specifically, the computing device may obtain a sum of the curvature atthe target sampling point and curvatures at the second auxiliary points,and divide the sum by a quantity of the summed curvatures, to obtain anaverage value of the curvature at the target sampling point and thecurvatures at the second auxiliary points.

In one embodiment, the computer obtains an average value of thecurvature at the target sampling point and the curvatures at the secondauxiliary points according to the following formula:K _(R)=(K _(F_pre) +K _(s) +K _(F_next))/n, whereK_(R) is an average value of a curvature at a target sampling point andcurvatures at second auxiliary points; K_(F_pre) is a curvature at asecond auxiliary point in front of the target sampling point; K_(s) isthe curvature at the target sampling point; K_(F_next) is a curvature ata second auxiliary point behind the target sampling point; and n is aquantity of curvatures to be summed. In one embodiment, if only onesecond auxiliary point is separately selected in front of and behind thetarget sampling point K_(s), n is 3.

In another embodiment, the computing device may directly use theobtained average value of the curvature at the target sampling point andthe curvatures at the second auxiliary points as the target curvature.In another embodiment, the computing device may alternatively use theobtained average value of the curvature at the target sampling point andthe curvatures at the second auxiliary points as the target curvature asa current reference curvature and obtain the target curvature withreference to a historical reference curvature.

In the foregoing embodiment, a sampling point having a maximum curvatureis first determined, and second auxiliary points are selected at apreset interval in front of or behind the sampling point having themaximum curvature, and a target curvature is determined according to acurvature at a target sampling point and curvatures at the secondauxiliary points. A target curvature obtained with reference to thecurvatures at the two auxiliary points in front and behind is morestable, and compared with a limitation of a curvature at a singlesampling point, can reflect a bending status of a traveling route moreaccurately, so that a corner can be found in advance, an further,accurate travel speed control is achieved by determining a speed limitbased on a curvature of the corner, thereby reducing sudden speedchanges and interference caused by speed planning.

In one embodiment, step S406 includes: generating a current referencecurvature according to an average value of the curvature at the targetsampling point and the curvatures at the second auxiliary points;obtaining a historical reference curvature; and using an average valueof the current reference curvature and the obtained historical referencecurvature as the target curvature.

The historical reference curvature is a reference curvature generatedbefore the current reference curvature. It may be understood that areference curvature is generated each time a speed limit is calculated,and the historical reference curvature is a reference curvaturegenerated during speed limit calculation before the current speed limitcalculation.

In another embodiment, the computing device may directly use theobtained average value of the curvature at the target sampling point andthe curvatures at the second auxiliary points as the current referencecurvature. The computing device may obtain all or some historicalreference curvatures. The computing device may obtain an average valueof the current reference curvature and the obtained historical referencecurvature, and use the average value as the target curvature.

In the foregoing embodiment, during target curvature calculation, atarget curvature is determined with reference to the current referencecurvature and the historical reference curvature or by obtaining anaverage value of the current reference curvature and the historicalreference curvature, so that the determined target curvature is morestable, which, compared with a limitation of being monotonously based onthe current reference curve, can reflect a bending status of a travelingroute more accurately.

As shown in FIG. 5, In one embodiment, the obtaining a historicalreference curvature (the historical reference curvature obtaining stepfor short) specifically includes the following steps.

S502: Obtain a speed limit calculation frequency and a preset selectiontime length.

The speed limit calculation frequency is a frequency at which a speedlimit is calculated. In one embodiment, the speed limit calculationfrequency may consistent with a speed planning frequency. The speedplanning frequency is a frequency at which a speed is planned. In oneembodiment, the speed limit calculation frequency may be 10 Hz. That is,a speed limit is calculated 10 times per 1 s.

The preset selection time length is used to determine a selection rangeof the historical reference curvature. The computing device may select ahistorical reference curvature generated within a preset selection timelength before a generation time of the current reference curvature. Forexample, if the preset selection time length is 1 s, the computingdevice may select a historical reference curvature generated within isbefore a generation time of the current reference curvature.

S504: Obtain a target quantity according to a product of the speed limitcalculation frequency and the preset selection time length.

The target quantity is a quantity of historical reference curvatures tobe selected.

In one embodiment, the computing device may directly use a product ofthe speed limit calculation frequency and the preset selection timelength as a target quantity. It may be understood that, in thisembodiment, the target quantity is also a quantity of historicalreference curvatures generated within a preset selection time lengthbefore the generation time of the current reference curvature.

For example, if a speed limit calculation frequency is 10 Hz, and apreset selection time length is 1 s, a target quantity=10*1=10.

S506: Obtain the target quantity of historical reference curvatures thatare recently generated before the current reference curvature isgenerated.

Specifically, the computing device may be select the first targetquantity of generated historical reference curvatures before a currentreference curvature is generated currently from the historical referencecurvatures generated before the current reference curvature isgenerated. For example, if the target quantity is 10, the computingdevice may select the first one, the first two, . . . until the firstten generated historical reference curvatures before a current referencecurvature is generated currently.

In the foregoing embodiment, a target quantity is obtained according toa product of the speed limit calculation frequency and the presetselection time length; and the target quantity of historical referencecurvatures that are recently generated are obtained before the currentreference curvature is generated. Then, the target curvature isdetermined according to an average value of the historical referencecurvature and the current reference curvature. That is, an average valueof the reference curvatures is calculated in a time dimension by usingthe speed limit calculation frequency, so that the final targetcurvature is an average value result in the time dimension, therebyfurther improving stability of the target curvature in the timedimension. Therefore, a speed limit determined according to a targetcurvature is more accurate, thereby preventing a sudden speed change.

As shown in FIG. 6, In one embodiment, step S406 (the target curvaturegenerating step for short) specifically includes the following steps.

S602: Obtain a current reference curvature according to an average valueof the curvature at the target sampling point and the curvatures at thesecond auxiliary points.

In another embodiment, the computing device may directly use theobtained average value of the curvature at the target sampling point andthe curvatures at the second auxiliary points as the current referencecurvature.

Specifically, the computing device may obtain a sum of the curvature atthe target sampling point and the curvatures at the second auxiliarypoints, and divide the sum by a quantity of the summed curvatures, toobtain current reference curvature.

S604: Obtain a previous generated target curvature.

The previous generated target curvature is a target curvature that isgenerated previous to current generation, that is, the target curvaturegenerated during speed limit calculation previous to currentcalculation.

S606: Average the current reference curvature and the previous generatedtarget curvature in a weighted manner according to a correspondingweight to generate a current target curvature.

In one embodiment, the computing device may generate a current targetcurvature according to the following formula:K _(A_now)=(1−a)*K _(A_pre) +a*K _(R_now),where K_(A_now) represents the current target curvature, K_(A_pre)represents the previous generated target curvature, K_(R_now) representsthe current reference curvature, and a is a weight of the currentreference curvature.

In one embodiment, a=1/H/T, H is a speed limit calculation frequency,and T is a preset selection time length. It may be understood that asthe number of iterations increases, a historical target curvature whosegeneration time is further from a current generation time has a smallerimpact on generation of a current target curvature, and finally, ahistorical target curvature generated within approximately a presetselection time length T before the current generation can have asubstantial impact on generation of the current target curvature. 1/H isa time length corresponding to generation of a current target curvature,and 1/H/T can reflect a proportion of a time length corresponding to thecurrent generated target curvature to an approximately total time lengthof the historical target curvature having an impact on generation of thecurrent target curvature, thereby determining a weight of a currentreference curvature. In one embodiment, H=10 Hz, and T=1 s.

In the foregoing embodiment, in an iterative calculation manner, aprevious generated target curvature serving as input, in combinationwith the current reference curvature, is averaged in a weighted manneraccording to a corresponding weight to generate a current targetcurvature. That is, with reference to average value calculation on thetarget curvature in a time dimension, a final target curvature is anaverage value result in the time dimension, thereby further improvingstability of the target curvature in the time dimensional. Therefore, aspeed limit determined according to a target curvature is more accurate,thereby preventing a sudden speed change.

As shown in FIG. 7, In one embodiment, another travel speed controlmethod is provided, specifically including the following steps:

S702: Determine a product of a current traveling speed and a preset timelength and obtain a preset sampling interval.

S704: Obtain a minimum value of the product of the current travelingspeed and the preset time length and the preset sampling interval as asampling interval.

S706: Select, starting from a current location, sampling points on anexpected traveling route according to the sampling interval.

S708: For each sampling point, consecutively select, starting from thesampling point, two first auxiliary points on the expected travelingroute by using a preset reference length that is less than the samplinginterval as an interval.

S710: Determine a curvature at the sampling point according to an angleformed by connection lines between the sampling point and the respectivefirst auxiliary points and a straight-line distance between the twofirst auxiliary points.

S712: Determine a target sampling point having a maximum curvature inthe respective sampling points.

S714: Select second auxiliary points respectively in front of and behindthe target sampling point on the expected traveling route according to apreset interval shorter than the sampling interval.

S716: Generate a current reference curvature according to an averagevalue of the curvature at the target sampling point and the curvaturesat the second auxiliary points.

S718: Obtain a speed limit calculation frequency and a preset selectiontime length, and obtain a target quantity according to a product of thespeed limit calculation frequency and the preset selection time length.

S720: Obtain the target quantity of historical reference curvatures thatare recently generated before the current reference curvature isgenerated, and use an average value of the current reference curvatureand the obtained historical reference curvature as the target curvature.

S722: Obtain a preset lateral force coefficient, and obtain an absolutevalue of the target curvature.

S724: Divide a product of the lateral force coefficient and theacceleration of gravity by the absolute value of target curvature andthen extract a square root to obtain the speed limit of traveling on theexpected traveling route.

S726: Control a traveling speed according to the speed limit.

In the foregoing travel speed control method, the sampling intervalmatches the current traveling speed, and sampling points are selected onthe expected traveling route according to the sampling interval, so thatthe sampling point are more likely to reflect requirements of travelspeed control at the current traveling speed. Determining the targetcurvature according to the curvatures at the selected sampling point canbetter reflect a bending status of the expected traveling route, so thata corner can be found in advance, and further, a speed limit isdetermined according to a curvature of the corner, thereby accuratelycontrolling a traveling speed and reducing sudden speed changes.

Second, by making two first auxiliary points, a relatively complexcalculus curvature calculation method is converted into directcalculation between an angle and a distance, which simplifies processingsteps and improves efficiency of obtaining curvatures at samplingpoints, thereby improving efficiency of driving speed control.

Then, a target curvature obtained with reference to the curvatures atthe two auxiliary points in front and behind is more stable, andcompared with a limitation of a curvature at a single sampling point,can reflect a bending status of a traveling route more accurately, sothat a corner can be found in advance, an further, accurate travel speedcontrol is achieved by determining a speed limit based on a curvature ofthe corner, thereby reducing sudden speed changes.

In addition, during target curvature calculation, a target curvature isdetermined with reference to the current reference curvature and thehistorical reference curvature or by obtaining an average value of thecurrent reference curvature and the historical reference curvature, sothat the determined target curvature is more stable, which, comparedwith a limitation of being monotonously based on the current referencecurve, can reflect a bending status of a traveling route moreaccurately.

Finally, an average value of the reference curvatures is calculated in atime dimension by using the speed limit calculation frequency, so thatthe final target curvature is an average value result in the timedimension, thereby further improving stability of the target curvaturein the time dimension. Therefore, a speed limit determined according toa target curvature is more accurate, thereby preventing a sudden speedchange.

As shown in FIG. 8, In one embodiment, a travel speed control apparatus800 is provided. The apparatus 800 includes: a sampling intervaldetermining module 802, a sampling point selection module 804, a targetcurvature determining module 808, a speed limit determining module 810,and a travel speed control module 812.

The sampling interval determining module 802 is configured to determinea sampling interval matching a current traveling speed.

The sampling point selection module 804 is configured to select,starting from a current location, sampling points on an expectedtraveling route according to the sampling interval.

The target curvature determining module 808 is configured to determine atarget curvature according to curvatures of the expected traveling routeat the respective sampling points.

The speed limit determining module 810 is configured to determine,according to the target curvature, a speed limit of traveling on theexpected traveling route.

The travel speed control module 812 is configured to control a travelingspeed according to the speed limit.

In one embodiment, the sampling interval determining module 802 isfurther configured to obtain a current traveling speed and a preset timelength; and determine a sampling interval according to a product of thecurrent traveling speed and the preset time length.

In one embodiment, the sampling interval determining module 802 isfurther configured to determine the product of the current travelingspeed and the preset time length; obtain a preset sampling interval; andobtain a minimum value of the product of the current traveling speed andthe preset time length and the preset sampling interval as the samplinginterval.

As shown in FIG. 9, In one embodiment, a travel speed control apparatus900 is provided. The apparatus 900 includes: a sampling intervaldetermining module 902, a sampling point selection module 904, a targetcurvature determining module 908, a speed limit determining module 910,and a travel speed control module 912.

The sampling interval determining module 902 is configured to determinea sampling interval matching a current traveling speed.

The sampling point selection module 904 is configured to select,starting from a current location, sampling points on an expectedtraveling route according to the sampling interval.

The target curvature determining module 908 is configured to determine atarget curvature according to curvatures of the expected traveling routeat the respective sampling points.

The speed limit determining module 910 is configured to determine,according to the target curvature, a speed limit of traveling on theexpected traveling route.

The travel speed control module 912 is configured to control a travelingspeed according to the speed limit.

In one embodiment, the sampling interval determining module 902 isfurther configured to obtain a current traveling speed and a preset timelength; and determine a sampling interval according to a product of thecurrent traveling speed and the preset time length.

In one embodiment, the sampling interval determining module 902 isfurther configured to determine the product of the current travelingspeed and the preset time length; obtain a preset sampling interval;obtain a minimum value of the product of the current traveling speed andthe preset time length and the preset sampling interval as the samplinginterval.

In some embodiments, the apparatus 900 further includes: an auxiliarypoint selection module 905, configured to: for each sampling point,consecutively select, starting from the sampling point, two firstauxiliary points on the expected traveling route by using a presetreference length that is less than the sampling interval as an interval;and a sampling point curvature determining module 906, configured todetermine a curvature at the sampling point according to an angle formedby connection lines between the sampling point and the respective firstauxiliary points and a straight-line distance between the two firstauxiliary points.

In one embodiment, the target curvature determining module 908 isfurther configured to determine a target sampling point having a maximumcurvature in the respective sampling points; select second auxiliarypoints respectively in front of and behind the target sampling point onthe expected traveling route according to a preset interval shorter thanthe sampling interval; and obtain the target curvature according to acurvature at the target sampling point and curvatures at the secondauxiliary points.

In one embodiment, the target curvature determining module 908 isfurther configured to generate a current reference curvature accordingto an average value of the curvature at the target sampling point andthe curvatures at the second auxiliary points; obtain a historicalreference curvature; and use an average value of the current referencecurvature and the obtained historical reference curvature as the targetcurvature.

In one embodiment, the target curvature determining module 908 isfurther configured to obtain a speed limit calculation frequency and apreset selection time length; obtain a target quantity according to aproduct of the speed limit calculation frequency and the presetselection time length; and obtain the target quantity of historicalreference curvatures that are recently generated before the currentreference curvature is generated.

In one embodiment, the target curvature determining module 908 isfurther configured to obtain a current reference curvature according toan average value of the curvature at the target sampling point and thecurvatures at the second auxiliary points; obtain a previous generatedtarget curvature; and average the current reference curvature and theprevious generated target curvature in a weighted manner according to acorresponding weight to generate a current target curvature.

In one embodiment, the target curvature determining module 908 isfurther configured to generate the current target curvature according tothe following formula:K _(A_now)=(1−a)*K _(A_pre) +a*K _(R_now),where K_(A_now) represents the current target curvature, K_(A_pre)represents the previous generated target curvature, K_(R_now) representsthe current reference curvature, and a is a weight of the currentreference curvature.

In one embodiment, The speed limit determining module 910 is furtherconfigured to: obtain a preset lateral force coefficient; obtain anabsolute value of the target curvature; and divide a product of thelateral force coefficient and the acceleration of gravity by theabsolute value of the target curvature and then extracting a square rootto obtain the speed limit of traveling on the expected traveling route.

FIG. 10 is a schematic diagram of an inner structure of a computingdevice In one embodiment. The computing device may be a terminal or aserver. The terminal may be a personal computer or a mobile electronicdevice, including at least one of a mobile phone, a tablet computer, apersonal digital assistant, wearable device, or the like. The server maybe an independent server or implemented by using a server clusterincluding multiple physical servers. Referring to FIG. 10, theelectronic device 1000 includes a processor 1002, a non-volatile storagemedium 1004, an internal memory 1006, and a network interface 1008 thatare connected through a system bus. The non-volatile storage medium 1004of the computing device may store an operating system 1010 and acomputer program 1012. The computer program 1012, when executed, maycause the processor to perform a travel speed control method. Theprocessor 1002 of the computing device is configured to providecalculation and control capabilities, to support running of the entirecomputing device. The internal memory 1006 may store the computerprogram 1012. When executed by the processor 1002, the computer program1012 may cause the processor 1002 to perform a travel speed controlmethod. The network interface 1008 of the computing device is configuredto perform network communication.

A person skilled in the art may understand that, the structure shown inFIG. 10 is merely a block diagram of a partial structure related to thesolutions of this application, and does not constitute a limitation tothe computing device to which the solutions of this application areapplied, and a specific computing device may include more or fewercomponents than those shown in the figure, or some components may becombined, or a different component deployment may be used.

In one embodiment, the travel speed control apparatus provided by thisapplication may be implemented in a form of a computer program. Thecomputer program may run on the computing device 1000 shown FIG. 10, andthe non-volatile storage medium of the computing device may storerespective program modules constituting the travel speed controlapparatus, for example, the sampling interval determining module 802,the sampling point selection module 804, the target curvaturedetermining module 808, the speed limit determining module 810, and thetravel speed control module 812, as shown in FIG. 8. The program modulesmay include one or more computer programs. The computer programs may beexecuted by one or more processors to cause the computing device toperform functions of the corresponding module and steps in the travelspeed control method of each embodiment of this application described inthis specification. For example, the computing device may determine, byusing the sampling interval determining module 802 in the travel speedcontrol apparatus 800 shown in FIG. 8, a sampling interval matching acurrent traveling speed; select, starting from a current location,sampling points on an expected traveling route according to the samplinginterval by using the sampling point selection module 804; determine atarget curvature according to curvatures at the respective samplingpoints by using the target curvature determining module 808; determine,according to the target curvature, a speed limit of traveling on theexpected traveling route by using the speed limit determining module810; and control a traveling speed according to the speed limit by usingthe travel speed control module 812.

In one embodiment, a computing device is provided, including: a memoryand a processor, the memory storing a computer program, and the computerprogram, when executed by the processor, causing the processor toperform the following steps: determining a sampling interval matching acurrent traveling speed; selecting, starting from a current location,sampling points on an expected traveling route according to the samplinginterval; determining a target curvature according to curvatures of theexpected traveling route at the respective sampling points; determining,according to the target curvature, a speed limit of traveling on theexpected traveling route; and controlling a traveling speed according tothe speed limit.

In one embodiment, the determining a sampling interval matching acurrent traveling speed includes: obtaining a current traveling speedand a preset time length; and determining a sampling interval accordingto a product of the current traveling speed and the preset time length.

In one embodiment, the determining a sampling interval according to aproduct of the current traveling speed and the preset time lengthincludes: determining the product of the current traveling speed and thepreset time length; obtaining a preset sampling interval; and obtaininga minimum value of the product of the current traveling speed and thepreset time length and the preset sampling interval as the samplinginterval.

In one embodiment, before the determining a target curvature accordingto curvatures at the respective sampling points, the computer programfurther causes the processor to perform the following steps: for eachsampling point, consecutively selecting, starting from the samplingpoint, two first auxiliary points on the expected traveling route byusing a preset reference length that is less than the sampling intervalas an interval; and determining a curvature at the sampling pointaccording to an angle formed by connection lines between the samplingpoint and the respective first auxiliary points and a straight-linedistance between the two first auxiliary points.

In one embodiment, the determining a target curvature according tocurvatures at the respective sampling points includes: determining atarget sampling point having a maximum curvature in the respectivesampling points; selecting second auxiliary points respectively in frontof and behind the target sampling point on the expected traveling routeaccording to a preset interval shorter than the sampling interval; andobtaining the target curvature according to a curvature at the targetsampling point and curvatures at the second auxiliary points.

In one embodiment, the obtaining the target curvature according to acurvature at the target sampling point and curvatures at the secondauxiliary points includes: generating a current reference curvatureaccording to an average value of the curvature at the target samplingpoint and the curvatures at the second auxiliary points; obtaining ahistorical reference curvature; and using an average value of thecurrent reference curvature and the obtained historical referencecurvature as the target curvature.

In one embodiment, the obtaining a historical reference curvatureincludes: obtaining a speed limit calculation frequency and a presetselection time length; obtaining a target quantity according to aproduct of the speed limit calculation frequency and the presetselection time length; and obtaining the target quantity of historicalreference curvatures that are recently generated before the currentreference curvature is generated.

In one embodiment, the obtaining the target curvature according to acurvature at the target sampling point and curvatures at the secondauxiliary points includes: obtaining a current reference curvatureaccording to an average value of the curvature at the target samplingpoint and the curvatures at the second auxiliary points; obtaining aprevious generated target curvature; and averaging the current referencecurvature and the previous generated target curvature in a weightedmanner according to a corresponding weight to generate a current targetcurvature.

In one embodiment, the averaging the current reference curvature and theprevious generated target curvature in a weighted manner according to acorresponding weight to generate a current target curvature includes:generating the current target curvature according to the followingformula:K _(A_now)=(1−a)*K _(A_pre) +a*K _(R_now), whereK_(A_now) represents the current target curvature, K_(A_pre) representsthe previous generated target curvature, K_(R_now) represents thecurrent reference curvature, and a is a weight of the current referencecurvature.

In one embodiment, the determining, according to the target curvature, aspeed limit of traveling on the expected traveling route includes:obtaining a preset lateral force coefficient; obtaining an absolutevalue of the target curvature; and dividing a product of the lateralforce coefficient and the acceleration of gravity by the absolute valueof the target curvature and then extracting a square root to obtain thespeed limit of traveling on the expected traveling route.

In one embodiment, a storage medium storing a computer program isfurther provided, the computer program, when executed by one or moreprocessors, causing the one or more processors to perform the followingsteps: determining a sampling interval matching a current travelingspeed; selecting, starting from a current location, sampling points onan expected traveling route according to the sampling interval;determining a target curvature according to curvatures of the expectedtraveling route at the respective sampling points; determining,according to the target curvature, a speed limit of traveling on theexpected traveling route; and controlling a traveling speed according tothe speed limit.

In one embodiment, the determining a sampling interval matching acurrent traveling speed includes: obtaining a current traveling speedand a preset time length; and determining a sampling interval accordingto a product of the current traveling speed and the preset time length.

In one embodiment, the determining a sampling interval according to aproduct of the current traveling speed and the preset time lengthincludes: determining the product of the current traveling speed and thepreset time length; obtaining a preset sampling interval; obtaining aminimum value of the product of the current traveling speed and thepreset time length and the preset sampling interval as the samplinginterval.

In one embodiment, before the determining a target curvature accordingto curvatures at the respective sampling points, the computer programfurther causes the processor to perform the following steps:

for each sampling point, consecutively selecting, starting from thesampling point, two first auxiliary points on the expected travelingroute by using a preset reference length that is less than the samplinginterval as an interval; and determining a curvature at the samplingpoint according to an angle formed by connection lines between thesampling point and the respective first auxiliary points and astraight-line distance between the two first auxiliary points.

In one embodiment, the determining a target curvature according tocurvatures at the respective sampling points includes: determining atarget sampling point having a maximum curvature in the respectivesampling points; selecting second auxiliary points respectively in frontof and behind the target sampling point on the expected traveling routeaccording to a preset interval shorter than the sampling interval; andobtaining the target curvature according to a curvature at the targetsampling point and curvatures at the second auxiliary points.

In one embodiment, the obtaining the target curvature according to acurvature at the target sampling point and curvatures at the secondauxiliary points includes: generating a current reference curvatureaccording to an average value of the curvature at the target samplingpoint and the curvatures at the second auxiliary points; obtaining ahistorical reference curvature; and using an average value of thecurrent reference curvature and the obtained historical referencecurvature as the target curvature.

In one embodiment, the obtaining a historical reference curvatureincludes: obtaining a speed limit calculation frequency and a presetselection time length; obtaining a target quantity according to aproduct of the speed limit calculation frequency and the presetselection time length; and obtaining the target quantity of historicalreference curvatures that are recently generated before the currentreference curvature is generated.

In one embodiment, the obtaining the target curvature according to acurvature at the target sampling point and curvatures at the secondauxiliary points includes: obtaining a current reference curvatureaccording to an average value of the curvature at the target samplingpoint and the curvatures at the second auxiliary points; obtaining aprevious generated target curvature; and averaging the current referencecurvature and the previous generated target curvature in a weightedmanner according to a corresponding weight to generate a current targetcurvature.

In one embodiment, the averaging the current reference curvature and theprevious generated target curvature in a weighted manner according to acorresponding weight to generate a current target curvature includes:generating the current target curvature according to the followingformula:K _(A_now)=(1−a)*K _(A_pre) +a*K _(R_now), whereK_(A_now) represents the current target curvature, K_(A_pre) representsthe previous generated target curvature, K_(R_now) represents thecurrent reference curvature, and a is a weight of the current referencecurvature.

In one embodiment, the determining, according to the target curvature, aspeed limit of traveling on the expected traveling route includes:obtaining a preset lateral force coefficient; obtaining an absolutevalue of the target curvature; and dividing a product of the lateralforce coefficient and the acceleration of gravity by the absolute valueof the target curvature and then extracting a square root to obtain thespeed limit of traveling on the expected traveling route.

A person of ordinary skill in the art should understand that all or apart of the processes of the method in the foregoing embodiment may beimplemented by a program instructing relevant hardware. The program maybe stored in a computer readable storage medium. When the program isrun, the processes of the method in the foregoing embodiment areperformed. The storage medium may be a non-volatile storage medium suchas a magnetic disk, an optical disc, or a read-only memory (ROM), or maybe a random access memory (RAM) or the like.

Technical features of the foregoing embodiments may be randomlycombined. To make description concise, not all possible combinations ofthe technical features in the foregoing embodiments are described.However, as long as combinations of these technical features do notcontradict each other, it should be considered that the combinations allfall within the scope recorded by this specification.

The foregoing embodiments only show several implementations of thisapplication and are described in detail, but they should not beconstrued as a limit to the patent scope of this application. It shouldbe noted that, a person of ordinary skill in the art may make variouschanges and improvements without departing from the ideas of thisapplication, which shall all fall within the protection scope of thisapplication. Therefore, the protection scope of the patent of thisapplication shall be subject to the appended claims.

What is claimed is:
 1. A travel speed control method, implemented on a computer and comprising: determining a sampling interval according to a current traveling speed by: obtaining the current traveling speed and a length of time; determining a product of the current traveling speed and the length of time; obtaining a preset sampling interval; and obtaining a minimum value of the product of the current traveling speed and the length of time and the preset sampling interval as the sampling interval; selecting, starting from a current location, sampling points on an expected traveling route according to the sampling interval, wherein the sampling points include a first, a second, and a third sampling points, the second sampling point is distanced from the first sample point by the sampling interval, and the third sampling point is distanced from the second sampling point by the sampling interval; determining a target curvature according to curvatures of the expected traveling route at the sampling points, wherein a curvature of the expected traveling route at the first sampling point of the sample points is determined by: starting from the first sampling point, selecting two first auxiliary points (first auxiliary point A and first auxiliary point B) on the expected traveling route, the two first auxiliary points are distanced from each other by a reference length that is shorter than the sampling interval; and determining the curvature at the first sampling point according to an angle formed by a connection line between the first sampling point and the first auxiliary point A, and a connection line between the first sampling point and the first auxiliary point B; determining, according to the target curvature, a speed limit of traveling on the expected traveling route; and controlling a traveling speed according to the speed limit.
 2. The method according to claim 1, wherein determining the target curvature according to the curvatures at the sampling points comprises: determining a target sampling point having a maximum curvature at the sampling points; selecting second auxiliary points respectively in front of and behind the target sampling point on the expected traveling route according to an interval shorter than the sampling interval; and obtaining the target curvature according to a curvature at the target sampling point and curvatures at the second auxiliary points.
 3. The method according to claim 2, wherein obtaining the target curvature according to the curvature at the target sampling point and the curvatures at the second auxiliary points comprises: generating a current reference curvature according to an average value of the curvature at the target sampling point and the curvatures at the second auxiliary points; obtaining a historical reference curvature; and using an average value of the current reference curvature and the historical reference curvature as the target curvature.
 4. The method according to claim 3, wherein obtaining the historical reference curvature comprises: obtaining a speed limit calculation frequency and a selection time length; obtaining a target quantity of historical reference curvatures according to a product of the speed limit calculation frequency and the selection time length; and selecting the historical reference curvature from the target quantity of historical reference curvatures.
 5. The method according to claim 2, wherein obtaining the target curvature according to the curvature at the target sampling point and the curvatures at the second auxiliary points comprises: obtaining a current reference curvature according to an average value of the curvature at the target sampling point and the curvatures at the second auxiliary points; obtaining a previously generated target curvature; and averaging the current reference curvature and the previously generated target curvature to generate the target curvature.
 6. The method according to claim 1, wherein determining the speed limit of traveling on the expected traveling route comprises: obtaining a lateral force coefficient; obtaining an absolute value of the target curvature; and dividing a product of the lateral force coefficient and the acceleration of gravity by the absolute value of the target curvature and then extracting a square root to obtain the speed limit of traveling on the expected traveling route.
 7. The method according to claim 1, wherein the current traveling speed falls within a range of traveling speeds, and each travel speed within the range corresponds to the preset sampling interval.
 8. A travel speed control apparatus, comprising: a memory storing computer program instructions; and a processor coupled to the memory and configured to execute the computer program instructions and perform: determining a sampling interval according to a current traveling speed by: obtaining the current traveling speed and a length of time; determining a product of the current traveling speed and the length of time; obtaining a preset sampling interval; and obtaining a minimum value of the product of the current traveling speed and the length of time and the preset sampling interval as the sampling interval; selecting, starting from a current location, sampling points on an expected traveling route according to the sampling interval, wherein the sampling points include a first, a second, and a third sampling points, the second sampling point is distanced from the first sample point by the sampling interval, and the third sampling point is distanced from the second sampling point by the sampling interval; determining a target curvature according to curvatures of the expected traveling route at the sampling points, wherein a curvature of the expected traveling route at the first sampling point of the sample points is determined by: starting from the first sampling point, selecting two first auxiliary points first auxiliary point A and first auxiliary point B) on the expected traveling route, the two first auxiliary points are distanced from each other by a reference length that is shorter than the sampling interval; and determining the curvature at the first sampling point according to an angle formed by a connection line between the first sampling point and the first auxiliary point A, and a connection line between the first sampling point and the first auxiliary point B; determining, according to the target curvature, a speed limit of traveling on the expected traveling route; and controlling a traveling speed according to the speed limit.
 9. The apparatus according to claim 8, wherein the processor is further configured to execute the computer program instructions and perform: determining a target sampling point having a maximum curvature at the sampling points; selecting second auxiliary points respectively in front of and behind the target sampling point on the expected traveling route according to an interval shorter than the sampling interval; and obtaining the target curvature according to a curvature at the target sampling point and curvatures at the second auxiliary points.
 10. A vehicle with a travel speed control apparatus, the travel speed control apparatus comprising: a memory storing computer program instructions; and a processor coupled to the memory and configured to execute the computer program instructions and perform: determining a sampling interval according to a current traveling speed of the vehicle by: obtaining the current traveling speed and a length of time; determining a product of the current traveling speed and the length of time; obtaining a preset sampling interval; and obtaining a minimum value of the product of the current traveling speed and the length of time and the preset sampling interval as the sampling interval; selecting, starting from a current location, sampling points on an expected traveling route according to the sampling interval, wherein the sampling points include a first, a second, and a third sampling points, the second sampling point is distanced from the first sample point by the sampling interval, and the third sampling point is distanced from the second sampling point by the sampling interval; determining a target curvature according to curvatures of the expected traveling route at the sampling points, wherein a curvature of the expected traveling route at the first sampling point of the sample points is determined by: starting from the first sampling point, selecting two first auxiliary points first auxiliary point A and first auxiliary point B) on the expected traveling route, the two first auxiliary points are distanced from each other by a reference length that is shorter than the sampling interval; and determining the curvature at the first sampling point according to an angle formed by a connection line between the first sampling point and the first auxiliary point A, and a connection line between the first sampling point and the first auxiliary point B; determining, according to the target curvature, a speed limit of traveling on the expected traveling route for the vehicle; and controlling a traveling speed of the vehicle according to the speed limit.
 11. The vehicle of claim 10, wherein processor is further configured to execute the computer program instructions and perform: determining a target sampling point having a maximum curvature at the sampling points; selecting second auxiliary points respectively in front of and behind the target sampling point on the expected traveling route according to an interval shorter than the sampling interval; and obtaining the target curvature according to a curvature at the target sampling point and curvatures at the second auxiliary points.
 12. The vehicle of claim 11, wherein the processor is further configured to execute the computer program instructions and perform: obtaining a current reference curvature according to an average value of the curvature at the target sampling point and the curvatures at the second auxiliary points; obtaining a previously generated target curvature; and averaging the current reference curvature and the previously generated target curvature to generate the target curvature.
 13. The vehicle of claim 10, wherein the processor is further configured to execute the computer program instructions and perform: obtaining a lateral force coefficient; obtaining an absolute value of the target curvature; and dividing a product of the lateral force coefficient and the acceleration of gravity by the absolute value of the target curvature and then extract a square root to obtain the speed limit. 